package com.ctrip.framework.apollo.portal.util.checker;

import com.google.common.base.Strings;

import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;

import org.springframework.stereotype.Component;

@Component
public class AuthUserPasswordChecker implements UserPasswordChecker {

    private static final Pattern PWD_PATTERN = Pattern.compile("^(?=.*[0-9].*)(?=.*[a-zA-Z].*).{8,20}$");

    private static final List<String> LIST_OF_CODE_FRAGMENT = Arrays.asList(
            "111", "222", "333", "444", "555", "666", "777", "888", "999", "000",
            "001122", "112233", "223344", "334455", "445566", "556677", "667788", "778899", "889900",
            "009988", "998877", "887766", "776655", "665544", "554433", "443322", "332211", "221100",
            "0123", "1234", "2345", "3456", "4567", "5678", "6789", "7890",
            "0987", "9876", "8765", "7654", "6543", "5432", "4321", "3210",
            "1q2w", "2w3e", "3e4r", "5t6y", "abcd", "qwer", "asdf", "zxcv"
    );

    @Override
    public CheckResult checkWeakPassword(String password) {
        if (!PWD_PATTERN.matcher(password).matches()) {
            return new CheckResult(Boolean.FALSE, "Password needs a number and letter and between 8~20 characters");
        }
        if (isCommonlyUsed(password)) {
            return new CheckResult(Boolean.FALSE,
                    "Passwords cannot be consecutive, regular letters or numbers. And cannot be commonly used. "
                            + "e.g: abcd1234, 1234qwer, 1q2w3e4r, 1234asdfghjk, ...");
        }
        return new CheckResult(Boolean.TRUE, null);
    }

    /**
     * @return The password contains code fragment or is blank.
     */
    private boolean isCommonlyUsed(String password) {
        if (Strings.isNullOrEmpty(password)) {
            return true;
        }
        for (String s : LIST_OF_CODE_FRAGMENT) {
            if (password.toLowerCase().contains(s)) {
                return true;
            }
        }
        return false;
    }
}
